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| Titel |
Comparing Lagrangian and Eulerian models for CO2 transport – a step towards Bayesian inverse modeling using WRF/STILT-VPRM |
| VerfasserIn |
D. Pillai, C. Gerbig, R. Kretschmer, V. Beck, U. Karstens, B. Neininger, M. Heimann |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1680-7316
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 12, no. 19 ; Nr. 12, no. 19 (2012-10-02), S.8979-8991 |
| Datensatznummer |
250011489
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| Publikation (Nr.) |
 copernicus.org/acp-12-8979-2012.pdf |
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| Zusammenfassung |
| We present simulations of atmospheric CO2 concentrations provided by
two modeling systems, run at high spatial resolution: the Eulerian-based
Weather Research Forecasting (WRF) model and the Lagrangian-based Stochastic
Time-Inverted Lagrangian Transport (STILT) model, both of which are coupled
to a diagnostic biospheric model, the Vegetation Photosynthesis and
Respiration Model (VPRM). The consistency of the simulations is assessed
with special attention paid to the details of horizontal as well as vertical
transport and mixing of CO2 concentrations in the atmosphere. The
dependence of model mismatch (Eulerian vs. Lagrangian) on models' spatial
resolution is further investigated. A case study using airborne measurements
during which two models showed large deviations from each other is analyzed
in detail as an extreme case. Using aircraft observations and pulse release
simulations, we identified differences in the representation of details in
the interaction between turbulent mixing and advection through wind shear as
the main cause of discrepancies between WRF and STILT transport at a spatial
resolution such as 2 and 6 km. Based on observations and inter-model
comparisons of atmospheric CO2 concentrations, we show that a
refinement of the parameterization of turbulent velocity variance and
Lagrangian time-scale in STILT is needed to achieve a better match between
the Eulerian and the Lagrangian transport at such a high spatial resolution
(e.g. 2 and 6 km). Nevertheless, the inter-model differences in simulated
CO2 time series for a tall tower observatory at Ochsenkopf in Germany
are about a factor of two smaller than the model-data mismatch and about a
factor of three smaller than the mismatch between the current global model
simulations and the data. |
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